Technical Writing
DMARC & Email Authentication Blog
DMARC, deliverability, and email authentication. Written for builders.
Jun 14, 2026
What Is DMARC Monitoring? The Visibility Layer Explained
DMARC monitoring is the ongoing practice of reading the aggregate reports your domain receives so you can see who's sending as you, whether they're aligning, and whether anyone is spoofing you. Here's what it watches and why raw reports are useless without it.
9 min readEmail AuthMonitoring
May 28, 2026
Is Your Domain Being Spoofed? Here's How to Find Out
If your domain has p=none or no DMARC record, you won't know if someone is sending email as your domain. Here's how to check, how to tell real spoofing from your own misconfigured senders, and exactly what to do to shut it down.
14 min readMonitoringEmail Auth
May 24, 2026
RFC 9989 DMARCbis: What Actually Changed for Your Domain
The first DMARC revision since 2015 dropped on May 20, 2026. Your existing record still works. Here's what changed and what you should actually do about it.
5 min readEmail Auth
May 14, 2026
How to Set Up BIMI: From p=reject to Your Logo in Gmail
A practical step-by-step guide for developers ready to add BIMI. Covers prerequisites, SVG format requirements, DNS records, the VMC decision, and how to verify it's working.
5 min readEmail Auth
May 13, 2026
Microsoft 365 DMARC Setup: Email Authentication in 4 Steps
Configure DKIM, SPF, and DMARC for Microsoft 365 so your domain stops failing authentication and you can monitor email delivery.
4 min readDKIMSPFEmail AuthSetup GuidesDeliverability
May 6, 2026
Set Up DMARC, SPF, and DKIM for Mailchimp
Domain authentication is now required in Mailchimp. Here's exactly what to add to your DNS and how to verify it's working.
5 min readSetup GuidesSPFDKIMEmail Auth
May 2, 2026
SPF Flattening: How to Fix Too Many DNS Lookups
SPF has a 10 DNS lookup limit. Add a few ESPs and you'll blow past it, causing PermError, silent DMARC alignment failures, and deliverability problems that are hard to trace. Here's how to fix it.
5 min readSPFEmail Auth
Apr 29, 2026
DMARC Failure Reports vs Aggregate Reports: RUF vs RUA Explained
RUF and RUA are two different DMARC reports. RUA gives you volume; RUF gives you forensics. Here's why most operators only care about one.
4 min readMonitoringEmail Auth
Apr 28, 2026
BIMI Explained: Show Your Logo in Email Inboxes
BIMI puts your logo next to emails you send. In Gmail, that requires a $1,500/yr certificate. In Yahoo Mail, it's free. Here's what BIMI is, how it works, and who should actually pursue it.
6 min readEmail Auth
Apr 22, 2026
Google Workspace DMARC and DKIM Setup Guide
Step-by-step guide to enable DKIM in Google Workspace Admin Console, configure SPF and DMARC records, and verify alignment so your emails deliver and you can monitor them.
7 min readDKIMSPFEmail AuthSetup Guides
Apr 15, 2026
How to Set Up DKIM and DMARC for SendGrid
Configure domain authentication, SPF, DKIM, and DMARC for SendGrid so your emails pass alignment and you can monitor delivery.
5 min readDKIMSPFEmail AuthSetup GuidesDeliverability
Apr 8, 2026
Cloudflare Email Routing and DMARC: Why Forwarded Mail Fails
Cloudflare Email Routing forwards inbound mail, but forwarding breaks SPF. Here's how DMARC, DKIM, and ARC work together to keep your forwarded mail in the inbox.
6 min readSPFDKIMEmail AuthSetup Guides
Apr 1, 2026
Email Forwarding and DMARC: Why Forwarded Mail Fails Authentication
Understand why email forwarding breaks SPF, how DKIM survives the hop, and when DMARC still passes; plus how ARC sealing fixes the problem.
5 min readSPFDKIMEmail AuthDeliverability
Mar 26, 2026
AWS SES DMARC Setup: Email Authentication in 5 Steps
Add DKIM, SPF, and DMARC to AWS SES so your emails pass authentication checks and you can monitor them with aggregate reports.
5 min readSPFDKIMSetup GuidesEmail Auth
Mar 19, 2026
Set Up DKIM and DMARC for Postmark
Configure sender signatures, DNS records, and DMARC for Postmark so your transactional emails pass authentication and you can monitor delivery.
5 min readDKIMSPFEmail AuthSetup GuidesDeliverability
Mar 17, 2026
SPF vs DKIM vs DMARC: How Email Authentication Really Works
SPF, DKIM, and DMARC aren't alternatives; they're layers. Here's what each one does and why you need all three.
6 min readSPFDKIMEmail Auth
Mar 12, 2026
How to Set Up DKIM and DMARC for Resend
Configure SPF, DKIM, and DMARC for Resend so your transactional emails pass authentication and you can monitor delivery.
4 min readDKIMSPFEmail AuthSetup GuidesDeliverability
Mar 5, 2026
DKIM vs DMARC: They're Not Alternatives
DKIM and DMARC are often confused because they're both email authentication tools. But they solve different problems. DKIM authenticates messages; DMARC enforces policy. You need both.
5 min readDKIMEmail Auth
Feb 19, 2026
What Is Email Authentication
Email authentication is the set of DNS-based protocols that verify an email comes from the domain it claims to. Learn how SPF, DKIM, and DMARC work together to prevent spoofing.
4 min readEmail AuthSPFDKIMGetting Started
Feb 12, 2026
What Is SPF (Sender Policy Framework)?
SPF publishes a DNS record listing servers authorized to send email for your domain. It protects the envelope sender, not the visible From header.
4 min readSPFEmail AuthDeliverability
Feb 5, 2026
What is DKIM? How Domain Key Authentication Works
DKIM adds a cryptographic signature to your emails so receiving servers can verify you sent them and they weren't modified in transit.
4 min readDKIMEmail AuthDeliverability